低18O碱性花岗岩成因讨论——以内蒙巴尔哲碱性花岗岩为例

巴尔哲花岗岩是一个罕见的亏损^18O的碱性花岗岩体，其中的石英、长石、钠闪石、锆石以及全岩的氧同位素含量都是国内碱性花岗岩中最低的。根据其氧同位素资料，结合岩体地质地球化学特征，讨论了该岩体以及我国东部低^18O碱性花岗岩的成因，认为用岩石与大气降水间同位素交换和开放体系下的岩浆去气作用解释该类岩石成因较为合理，但也有缺陷，有待进一步研究。

A discussion on the petrogenesis of 18O-low alkali granite--A case study of Baerzhe alkali granite in Inner Mongolia

Baerzhe granite in Inner Mongolia is a rare rock depleted in 18 O. This paper gives the oxygen isotopic values of quartz, feldspar, riebeckite, zircon and whole rock of Baerzhe alkali granite, which seem to be the lowest among these isotopic values in all the alkali granites of China. In the light of isotopic data, this paper deals with geological and geochemical characteristics, the origins of Baerzhe rock body and the 18 O_low alkali granites in eastern China. The authors consider that two arguments are relatively reasonable for illustrating the petrogenesis: one is isotope exchange between the rock and the meteoric water, and the other is magmatic degassing of the rock in an open system. The problem of petrogenesis deserves further researches.